[SILParser] parsing extensions.

Fix a bug introduced in r20818, where we should print get for computed property.
Make sure we can round-trip extension of a generic class and extension of an
inner class.

rdar://17927072


Swift SVN r21151

Author: Manman Ren

lib/AST/ASTPrinter.cpp

@@ -582,12 +582,16 @@ bool PrintAST::shouldPrint(const Decl *D) {
 
 void PrintAST::printAccessors(AbstractStorageDecl *ASD) {
   // If we are printing StoredWithTrivialAccessors in sil, print get|set
-  // to differentiate from stored property.
+  // to differentiate from stored property. FIXME: Parser can't handle
+  // "let {get}", so do not print it.
   if (!ASD->hasAccessorFunctions() ||
-      (Options.PrintForSIL && !ASD->getSetter()) ||
+      (Options.PrintForSIL &&
+       ASD->getStorageKind() == AbstractStorageDecl::StoredWithTrivialAccessors
+       && isa<VarDecl>(ASD) && cast<VarDecl>(ASD)->isLet() &&
+       !ASD->getSetter()) ||
       (!Options.PrintForSIL &&
        ASD->getStorageKind()
-       == AbstractStorageDecl::StoredWithTrivialAccessors)){
+       == AbstractStorageDecl::StoredWithTrivialAccessors)) {
     // This is a 'let' vardecl.  We could print the initializer if we could
     // print expressions.
     return;
@@ -860,6 +864,19 @@ void PrintAST::visitExtensionDecl(ExtensionDecl *decl) {
       // We cannot extend sugared types.
       auto *nominal = decl->getExtendedType()->getAnyNominal();
       assert(nominal && "extension of non-nominal type");
+      
+      if (auto ct = decl->getExtendedType()->getAs<ClassType>()) {
+        if (auto ParentType = ct->getParent()) {
+          ParentType.print(Printer, Options);
+          Printer << ".";
+        }
+      }
+      if (auto st = decl->getExtendedType()->getAs<StructType>()) {
+        if (auto ParentType = st->getParent()) {
+          ParentType.print(Printer, Options);
+          Printer << ".";
+        }
+      }
       Printer.printTypeRef(nominal, nominal->getName());
     });
   printInherited(decl);

lib/SIL/SILPrinter.cpp

@@ -1508,7 +1508,8 @@ void SILModule::print(llvm::raw_ostream &OS, bool Verbose,
     SmallVector<Decl *, 32> topLevelDecls;
     M->getTopLevelDecls(topLevelDecls);
     for (const Decl *D : topLevelDecls) {
-      if ((isa<ValueDecl>(D) || isa<OperatorDecl>(D)) &&
+      if ((isa<ValueDecl>(D) || isa<OperatorDecl>(D) ||
+           isa<ExtensionDecl>(D)) &&
           !emittedFunctions.count(D) &&
           !D->isImplicit()) {
         D->print(OS, Options);

test/SIL/Parser/extension.swift

@@ -0,0 +1,25 @@
+// RUN: %swift %s -emit-silgen | sil-opt -verify
+
+public struct X {
+}
+
+extension X {
+  public struct Y {}
+}
+
+extension X.Y {
+  var startIndex: Int {
+    return 0
+  }
+}
+
+class X2<T> {
+}
+
+extension X2 {
+  var startIndex: Int {
+    return 0
+  }
+}
+
+public func ==(lhs: X.Y, rhs: X.Y) -> Bool { return true }